Azimuth adjustment device with lock for firearm sights



V SEARCH mm Sept. 13, 1966 J. G. ROCHA 3,271,864

AZIMUTH ADJUSTMENT DEVICE WITH LOOK FOR FIREARM SIGHTS Filed March 17,1964 2 Sheets-Sheet 1 INVENTOR ATTORNEYS Sept. 13, 1966 oc 3,271,864

AZIMUTH ADJUSTMENT DEVICE WITH LOCK FOR FIREARM SIGHTS Filed March 17,1964 2 Sheets-Sheet 2 INVENTOR John llRuchu ATTORNEYS United StatesPatent 3 271,864 AZIMUTH ADJUSTlVlENT DEVICE WITH LOCK FOR FIREARMSIGHTS John G. Rocha, Westfield, Mass., assignor to the United States ofAmerica as represented by the Secretary of the Naw Filed Mar. 17, 1964,Ser. No. 352,696 3 Claims. (Cl. 33-56) The invention described hereinmay be manufactured and used by or for the Government for governmentalpurposes without the payment to me of any royalty thereon.

This invention relates to gun sights and pertains more particularly togun sights which are adjustable as to range and azimuth drift.

Certain shoulder arms, such as the M79 Grenade Launcher, are designedfor high trajectory fire whereby the sight line for distant ranges mustbe elevated at a considerable angle relative to the bore axis of thegun. Because of this, the sights for such guns must be designed so thatthe gun structure will not interfere with the angular adjustment of thesights between the minimum and maximum ranges; whereby, the sight has tobe offset respective to its point of mounting on the gun to be free ofinterference with the gun barrel. This means that where severe recoilshocks are created high torque forces are produced in the sight at themounting axis so that it is impossible to maintain an azimuth adjustmentwith conventional types of adjustment devices.

It is, therefore, the principal object of this invention to provide suchsights with an azimuth adjustment device in the axial mount thereof andmeans for locking the sight in its adjusted azimuth position.

The specific nature of the invention as well as other objects andadvantages thereof will clearly appear from a description of a preferredembodiment as shown in the accompanying drawings in which:

FIG. 1 is an elevational view of a high trajectory sight mounted on afirearm barrel;

FIG. 2 is a view taken along line 2-2 of FIG. 1;

FIG. 3 is a view taken along line 3-3 of FIG. 2;

FIG. 4 is a view taken along line 44 of FIG. 2;

FIG. 5 is a view taken along line 55 of FIG. 2;

FIG. 6 is a fragmentary view similar to FIG. 2 but showing the lockingmember actuated to secure the azimuth adjustment device in the selectedposition; and

FIG. 7 is a perspective exploded view of the sight mount and the azimuthadjustment device therein.

Shown in the figures is a gun barrel 12 with a pad 14 integrally formedthereon for mounting a sight 16. Sight 16 includes a base plate 18 whichis fastened to pad 14 and a sector member 20 which is mounted onto thebase plate, as hereinafter described, so as to be swung by an azimuthadjustment device 22 around the vertical axis thereof. An optical sighttube 24 is mounted on sector member 20 for calibrated range adjustment.

Formed on top of base plate 18 is a boss 26 which is recessed at thetop, as noted at 28, to form a rib 30 and a groove 32 bot-h of which areof U-configuration in lateral cross-section. A bore 34 extendsvertically through base plate 18 and boss 26 from recess 28 and suchbore is counterbored at 36 from the bottom end to form a shoulder 38.Recess 28 receives the bottom end of a mount 40 which is fixed at oneside, as by welding, to seetor member 20 and which has a flange 42formed around the base :so as to be received by groove 32 to hold themount against vertical displacement. Mount 40 is substantially ofU-configuration in lateral cross-section. However, the sides of mount 40and flange 42 taper inwardly toward-s the side to which sector member 20is fixed to provide clearance for limited rotational displace- 3,271,864Patented Sept. 13, 1966 ment of the mount in recess 28 around theextended axis of bore 34.

A bottomed hole 48 having the same diameter as bore 34 extends upwardlyinto mount 40 from the bottom end thereof in axial alignment with suchbore. An aperture 50 extends concentrically from hole 48 through the topof mount 40. Bore 34 and hole 48 receive a pintle 52 of similar diameterwhich acts as a bearing for the rotational displacement of mount 40. Arib 54 around the bottom of pintle 52 is received by counterbore 36 tolimit vertical displacement of the pintle. Rotational displacement ofpintle 52 is prevented by a pin 55 which extends transversely throughbase plate 18 and a vertical slot 56 that extends upwardly into pintle52 from the bottom end thereof.

Vertical displacement of pintle 52 is converted to rotationaldisplacement of mount 40 through the cooperation of a pair of camfollowers 58 installed in the mount with a pair of cam slots 60 formedin the pintle. Vertical displacement of pintle 52 is effected by a shaft62 which is threaded at one end, as noted at 64, to engage with a matingthreaded bore 66 in the pintle. The opposite end of shaft 62 extendsupwardly through aperture 50 and mounted on such extended end is a knob68 which provides means for manually rotating the shaft.

Fixedly mounted on shaft 62 within hole 48 and above threaded portion 64is a sprocket wheel 70 which is provided with a plurality ofsubstantially semicircular recesses 72 formed between teeth 74. Theoverall diameter of sprocket wheel 70 is similar to that of hole 48.Contact of the bottom of knob 68 with the outside of top 75 of mount 40and the contact of sprocket wheel 70 with the inside of the top holdsshaft 62 against vertical displacement.

Extending downwardly into mount 40 from the top thereof is a keyholeslot 76 which slidingly receives a plunger 78 having a key portion 80 toprevent rotation thereof. Plunger 78 is biased upwardly in keyhole slot76 by a spring 82. An orifice 84 provides communication between keyholeslot 76 and hole 48 in registry with sprocket wheel 70 and slidinglyreceived by such orifice is a metallic ball 86 having the same radius asrecesses 72. A substantially semicylindrical pocket 88 is transverselyformed in plunger 78 so as to be in registry with orifice 84 when thetop of the plunger is flush with top 75 of mount 40. Orifice 84 has adiameter similar to that of ball 86 and a length equal to the radiusthereof and the radii of recesses 72 and pocket 88 are the same as thatof the ball so that, when plunger 78 is in an unlocked position withpocket 88 in registry with the orifice, shaft 62 may be freely turned asteeth 74 cam ball 86 free thereof into the pocket and so that, when theplunger is displaced upwardly to a locked position with the pocket movedout of registry with the orifice, the ball is forced into the one of therecesses which is in registry with the orifice to block the shaftagainst rotation.

Plunger 78 is actuatable between the locked and unlocked positions by aring-type locking member 90 which is rotatingly mounted on a reduceddiameter bearing section 92 of knob 68 in contact with top 75 of mount40 and so that the underside of the locking member has contact with thetop of plunger 78 to hold the plunger in the unlocked position. Providedin the underside of locking member 90 is a notch 94 which, when inregistry with plunger 78, permits the plunger to be displaced upwardlyby spring 82 to the locked position.

Operation When sight 16 is to be adjusted to compensate for ballistic orwindage drift, locking member 90 is turned to where notch 94 is disposedout of registry with plunger 78 so that the plunger is displaceddownwardly to the unlocked position. With plunger 78 in the unlockedposition, pocket 88 is in registry with orifice 84 so that ball 86 maybe displaced thereinto out of interference with sprocket wheel 70 whenknob 68 is rotated. Sect-or member 20 is swung around pintle 52 to thecorrected position by turning knob 68 which causes rotation of shaft 62and, therefore, vertical displacement of pintle 52 through thecooperation of threaded portion 64 with threaded bore 66. Verticaldisplacement of pintle 52 is converted to rotational displacement ofmount 40 and, therefore, sector member 20 through the cooperation ofca-m slots 60 in the pintle with cam followers 58 in the mount. When thecorrect adjustment is made, sector member 20 is locked in position byturning locking member 90 to where notch 94 is in registry with plunger78 so that the plunger is displaceable by spring 82 to the lockedposition. With plunger 78 located in the locked position, half of ball86 is located in one of the recesses 72 while the other half is locatedin orifice 84, thereby blocking rotation of sprocket Wheel 70 to holdsector member 20 against displacement. If one of the recesses 72 is notin complete alignment with orifice 84, any slight displacement of shaft62 will bring one into alignment without affecting the adjusted positionof sight tube 24 because of the high ratio of turn relationship betweenthe shaft and mount 40.

Although a particular embodiment of the invention has been described indetail herein, it is evident that many variations may be devised withinthe spirit and scope thereof and the following claims are intended toinclude such variations.

I claim:

1. A firearm sight having a base plate, a mount mounted on said baseplate for rotational displacement respective thereto around a verticalaxis, a sector member fixed to one side of said mount, a sight tubemounted on said sector member for calibratedTa fi geadjustment, anazimuth adjustment device having a pintle received by a mating hole insaid mount and a bore in said base plate so as to act as a bearing forthe rotational displacement of said mount and means for adjustablyrotating said mount around said pintle, and means for releasably lockingsaid mount at its adjusted position including a transverse pin throughsaid base plate slidingly received by a vertical slot in said pintle toprevent rotation thereof respective to said base plate, means fordisplacing said pintle vertically, a pair of cam slots formed in saidpintle, and a pair of cam followers on said mount having slidingengagement with said cam slots for converting vertical displacement ofsaid pintle to rotational displacement of said mount.

2. The sight as defined in claim 1 wherein said means for displacingsaid pintle vertically include a shaft coaxially related to said pintle,means for threadingly engaging said shaft to said pintle, means forholding said shaft against axial displacement, and a knob mounted onsaid shaft to provide for rotational displacement thereof.

3. The sight as defined in claim 2 wherein said means for releasablylocking said mount includes a sprocket wheel fixed to said shaft withinsaid hole, a plurality of semicircular recesses formed between teetharound said sprocket wheel, a keyhole slot formed in said mount from thetop thereof parallel to said hole, an orifice providing communicationbetween said slot and said hole in registry with said sprocket wheel, aplunger slidingly disposed in said slot, a semicylind'rical pockettransversely formed in said plunger for registry with said orifice whena top end of said plunger is flush with a top of said mount, a ballslidingly received by said orifice, said orifice having a diameter equalto that of said ball and a length equal to the radius thereof and saidpocket and said recesses having radii equal to the radius of said ball,a spring for biasing said plunger upwardly in said slot, a lockingmember rotatingly mounted on said knob for contact with the top of saidmount and the top end of said plunger to hold the top end thereof flushwith the top of said mount, and a pocket formed in the underside of saidlocking member for registry with said plunger to permit upperdisplacement thereof by said spring to move said pocket out of registrywith said orifice when said pocket and said plunger are in registry.

References Cited by the Examiner UNITED STATES PATENTS 723,476 3/1903 DeMesquita 33-48 2,015,627 9/1935 Hug 33-69 LEONARD FORMAN, PrimaryExaminer.

S. S. MATTHEWS, Assistant Examiner.

1. A FIREARM SIGHT HAVING A BASE PLATE, A MOUNT MOUNTED ON SAID BASEPLATE FOR ROTATIONAL DISPLACEMENT RESPECTIVE THERETO AROUND A VERTICALAXIS, A SECTOR MEMBER FIXED TO ONE SIDE OF SAID MOUNT, A SIGHT TUBEMOUNTED ON SAID SECTOR MEMBER FOR CALIBRATED RANGE ADJUSTMENT, ANDAZIMUTH ADJUSTMENT DEVICE HAVING A PINTLE RECEIVED BY A MATING HOLE INSAID MOUNT AND A BORE IN SAID BASE PLATE SO AS TO ACT AS A BEARING FORTHE ROTATIONAL DISPLACEMENT OF SAID MOUNT AND MEANS FOR ADJUSTABLYROTATING SAID MOUNT AROUND SAID PINTLE, AND MEANS FOR RELEASABLY LOCKINGSAID MOUNT AT ITS ADJUSTED POSITION INCLUDING A TRANSVERSE PIN THROUGHSAID BASE PLATE SLIDINGLY RECEIVED BY A VERTICAL SLOT IN SAID PINTLE TOPREVENT ROTATION THEREOF RESPECTIVE TO SAID BASE PLATE, MEANS FORDISPLACING SAID PINTLE VERTICALLY, A PAIR OF CAM SLOTS FORMED IN SAIDPINTLE, AND A PAIR OF CAM FOLLOWERS ON SAID MOUNT HAVING SLIDINGENGAGEMENT WITH SAID CAM SLOTS FOR CONVERTING VERTICAL DISPLACEMENT OFSAID PINTLE TO ROTATIONAL DISPLACEMENT OF SAID MOUNT.